It's the first time voters will be asked to ban same-sex marriage in a state where gay couples already have won the right to wed. Same-sex marriage is legal in Massachusetts and California.

It's the first time voters will be asked to decide the issue in either California or Massachusetts -- the states where gays have won the right to wed.

"Because no one has the right to deny another their life, even though they disagree with it, because everyone has the right to live the life they so desire if it doesn't harm another and because discrimination has no place in America, my vote will be for equality and against Proposition 8," Pitt said Wednesday.

Trevor Neilson, Pitt's political and philanthropic adviser, told The Associated Press that Pitt was surprised that his colleagues in the entertainment industry had not donated more money to support the battle against Proposition 8.

Earlier in the week, Pitt and Angelina Jolie announced they donated $2 million to help fight HIV/AIDS and tuberculosis in Ethiopia.

Actor Brad Pitt has donated $100,000 to fight a California's ballot initiative that would overturn the state Supreme Court decision legalizing same-sex marriage.